As a novel bionic analytical technique, an electronic nose, inspired by the mechanism of the biological olfactory system and integrated with modern sensing technology, electronic technology and pattern recognition technology, has been widely used in many areas. Moreover, recent basic research findings in biological olfaction combined with computational neuroscience promote its development both in methodology and application. In this review, the basic information processing principle of biological olfaction and artificial olfaction are summarized and compared, and four olfactory models and their applications to electronic noses are presented. Finally, a chaotic olfactory neural network is detailed and the utilization of several biologically oriented learning rules and its spatiotemporal dynamic propties for electronic noses are discussed. The integration of various phenomena and their mechanisms for biological olfaction into an electronic nose context for information processing will not only make them more bionic, but also perform better than conventional methods. However, many problems still remain, which should be solved by further cooperation between theorists and engineers.artificial olfaction, olfactory model, pattern recognition, electronic nose, bionics Various sensors derive different types of information from complicated environments, following which computers analyze before actuators perform particular tasks. To a certain degree, such devices have extended human sensory, brain and physical power to enhance the capacity of understanding and transforming nature. However, biological systems derived from evolution are useful models for engineering design, particularly with regard to bionics.Electronic noses (eNose) are a kind of novel bionic analytical instrument for mimicking the principle of biological olfaction. Generally, an electronic nose consists of an array of cross-sensitive gas sensors and an appropriate pattern recognition method, capable of automatically detecting and discriminating simple or complex odors [1] . Only twenty years after Persaud et al.'s pioneer work [2] , eNoses have been widely utilized within the food industry, for environmental monitoring, public security and medical diagnosis [3,4] , as they tend to be relatively fast, easy to use and objective with a modest overall cost.As a multidisciplinary research field, most studies of eNose primarily focus on gas sensor technology [5] and pattern recognition methods [6] . Pattern recognition models remain inadequately investigated such that they are the bottle-neck for commercialization. With more novel sensing techniques are applied to eNoses [3,7] , signal processing and pattern recognition methods have increased in significance. The information processing mechanism in olfaction from the genetic, cellular to systemic levels is more fully understand as a result of cross-